This invention will find use when processing any one of a number of plants or plant material, the preferred one of which is the soybean.
Those who are skilled in the art will readily perceive a variety of other plants or plant material which may be used, for example, red clover, kudzu, alfalfa, tea, cocoa, and subterranean clover are also expected to work in this invention. Accordingly, the terms plant, plant material, vegetable matter, and vegetable are to be construed herein as including these and other suitable materials.
As used herein, the term xe2x80x9cisoflavonexe2x80x9d is a flavonoid and includes saponins, lignans, alkaloids, catechins, and phenolic acids and also includes malonyl, acetyl, glucoside, and aglycone forms of the isoflavones.
For some background information on processing soy, reference may be made to the following articles: xe2x80x9cIsolated Soy Proteinxe2x80x9d by C. W. Kolar, S. H. Richert, C. D. Decker, F. H. Steinke, and R. J. VanderZanden, found as chapter VIII of New Protein Foods, Vol. 5, eds. Aaron M. Altschul and Harold L. Wilcke, Academic Press, Inc. 1985; xe2x80x9cTraditional Soyfoods: Processing and Productionxe2x80x9d by Peter Goldbitz; and xe2x80x9cSoy Protein Products: Processing and Usexe2x80x9d by Edmund W. Lusas and Mian N. Raz, both (0022-3166/95) published 1995 by the American Institute of Nutrition. A process for producing soy whey is disclosed on pages 386, 387 of xe2x80x9cSoybeans Chemistry, Technology, and Utilizationxe2x80x9d by KeShun Liu, published by Chapman and Hall, 115 Fifth Avenue, New York, N.Y. 10003.
Isoflavones are a unique class of plant flavonoids that have a limited distribution in the plant kingdom and may be physically described as colorless, crystalline phenolic ketones. The most common and important dietary source of these isoflavones are soybeans which contain the following twelve isoflavone isomers: genistein, genistin, 6xe2x80x3-0-malonylgenistin, 6xe2x80x3-0-acetylgenistin; daidzein, daidzin, 6xe2x80x3-0-malonyldaidzin, 6xe2x80x3-0-acetylgenistin; glycitein, glycitin, 6xe2x80x3-0-malonylglycitin, 6xe2x80x3-0-acetylglycitin (Kudou, Agric. Biol. Chem. 1991, 55, 2227-2233). Ninety-seven to ninety-eight percent of the soybean isoflavones are in the glycosylated form.
Traditionally, individuals have been limited in their use of soy foods to increase their levels of dietary isoflavones because the number and variety of soy foods is limited especially in the U.S. marketplace. Also, natural flavors and color of some soy products have been described by some people as being bitter and unappetizing.
The isoflavone, genistin, was first isolated from soybean meal in 1931 by Walz (Justus Liebigs Ann. Chem 489, 118) and later confirmed in 1941 by Walter (J. Amer. Chem. Soc. 63, 3273). Patents have described the production of isoflavone enriched soy-protein products (WO 95/10512; WO95/10529; WO 95/10530), genistin malonate and daidzin malonate (U.S. Pat. No. 5,141,746), pharmaceutical-type compositions containing isoflavones (U.S. Pat. Nos. 5,424,331; 4,883,788), and isolation and modification of isoflavones from tempeh (U.S. Pat. Nos. 4,390,559; 4,366,248; 4,366,082; 4,264,509; 4,232,122; 4,157,984). The present invention relates to the manufacture of highly enriched isoflavone products containing either a wide-range of soy isoflavones or highly-purified genistin gained from an ethanol extract of defatted soybean flakes.
For example, coronary heart disease (CHD) is a leading cause of death, especially in the United States and other industrialized nations. Elevated total and low density lipoprotein (LDL) cholesterol levels are important risk factors for CHD. In humans, soy protein products appear to lower serum total cholesterol levels by an average of about 9.3% and to lower low-density lipoprotein (LDL) cholesterol by an average of about 12.9% when consumed at an average intake level of 47 g soy protein per day (Anderson et al., NEJM, 333: 276-282, 1995).
Isoflavones (phytoestrogens) are implicated as a class of compounds in soy protein products which is at least partly responsible for this cholesterol-lowering effect in animals (Setchell, in McLachlan JA, ed., Estrogens in the Environment II: 69-85, 1985). In addition, studies with primates suggest that soy isoflavones may account for up to about 60-70% of the hypocholesterolemic properties of soy protein (Anthony et al., Circulation, 90: Suppl: I-235. (abstract), 1994; Anthony et al., J. Nutr., 125: Suppl 3S: 803S-804S. (abstract), 1995; Anthony et al., Circulation, 91: 925. (abstract), 1995).
It has also been suggested that isoflavones have an ability to play a role in the prevention of certain cancers. Japanese women who have consumed diets rich in isoflavones appear to have a very low incidence of breast cancer (Adlercreutz et al., J. Nutr. 125: 757S-770S, 1995). Soy products have also been shown to decrease mammary tumor formation or to inhibit mammary tumor progression in rat breast cancer models (Barnes et al., Clin. Biol. Res. 347: 239-253; Hawrylewicz et al., J. Nutr. 121: 1693-1698, 1991). Genistein has been shown to inhibit protein tyrosine kinase (Akiyama et al., J. Biol. Chem. 262: 5592-5595, 1987), to inhibit angiogenesis (Fotsis et al., Proc. Natl. Acad. Sci. USA 90: 2690-2694, 1993), and to induce differentiation in several malignant cell lines (Peterson, J. Nutr. 125: 784S-789S, 1995), all of which may be important risk factors in cancer development. Genistein and Biochanin A also appear to inhibit the growth of androgen-dependent and independent prostatic cancer cells in vitro (Peterson and Barnes, Prostate 22: 335-345, 1993). Genistein may act as an antioxidant (Wei et al., Nutr. Cancer 20: 1-12, 1993).
Beyond cancer, it is thought that at least some of the soy isoflavone fractions are especially beneficial for women in general since it is a source of plant or vegetable estrogen. It is thought that plant or vegetable estrogen provides many of the advantages and avoids some of the alleged disadvantages of animal estrogen. Hence, it is especially desirable to enable the isoflavone fractions to be used in a wide variety of ways, such as in beverages and foods including health bars. This means that the isoflavone fractions should not introduce unacceptable tastes or unappetizing colors.
Some of these medical conditions may be either preventable or treatable by a use of phytochemicals, especially isoflavones, as a source of supplemental hormones. Hence, proper diet should contain the desired phytochemicals.
It is also thought that there are superior results when a plurality of such phytochemicals are consumed in proper combinations. However, a trouble is that many people do not have or do not like the proper kind of diet which provides the desirable effects. Therefore, the problem is to furnish the necessary food values in some other form. Accordingly, it is desirable to provide a refinement process which is able to provide a selected combination of phytochemicals tailored to a specific symptom.
The process described in U.S. Pat. Nos 5,702,752; 6,017,555; and 6,033,714 produce an excellent concentration of isoflavones. However, the end product could be improved and produced at lower cost especially by reducing the energy required to dry an aqueous feed stream carrying the isoflavone fractions. Also, it is desirable to increase the concentration of the isoflavone fraction in the end product. Isoflavones are preferably formed into pills, tablets, capsules, liquids, and food ingredients which may be ingested without having to taste the original food product. Also, there are times when it is desirable to use the isoflavones as supplements in foods, beverages, medical foods, health bars, and certain other dietary supplement products.
Accordingly, an object of this invention is to provide a combination of isoflavone fractions which have a neutral color and a bland flavor, and which together provide a profile especially directed to specific health problems. In particular, an object is to provide a supplement which may be included in a great variety of foods and beverages. More particularly, an object is to provide isoflavone materials of greater concentration where smaller quantities of a supplement deliver the same amount or more of the desired isoflavones.
Another object is to provide a process that uses soy whey, which has sometimes been an unacceptable starting material for use in more important and valuable products; therefore, it is often generated as a by-product of soy processing.
A still further object of the invention is to provide a process that results in an intermediate product that can be conveniently stored for later processing into a pure form when required. Another object is to provide a process that requires less equipment and less time to produce a more consistently pure product at a lower cost, especially a product with a greater concentration of isoflavones.
In keeping with an aspect of the invention, a product resulting from a removal of alcohol from an aqueous alcohol feed stream of vegetable material containing at least two isoflavone fractions is treated with either reverse osmosis or ultrafiltration (or both) in order to achieve a higher concentration of isoflavone solids in the end product. This process of reverse osmosis or ultrafiltration (or both) prior to drying to a dry product reduces the amount of evaporation as compared to the former process in order to produce a significant reduction in energy demand, and therefore, the cost of the process. Then, the feed stream is dried to a dry product, such as powder, preferably by spray drying. Optional steps including redissolving the dry product, concentrating the redissolved product, separating and redrying the crystals. As a result, the isoflavone concentration in the product before spray drying is 1%-10% solids and preferably 4%-7% solids.
In keeping with other aspects of the invention, these and other objects are accomplished by starting preferably with soy molasses, or alternatively with soy whey, which is subjected to ultra-filtration in order to produce a permeate which then passes through a column containing an adsorbing resin. The resin is then washed with water and eluted with aqueous alcohol, preferably ethanol. In the Assignee""s previous patent, the next step evaporates alcohol until the solids are in the range of approximately 1-20% of the remaining liquid. This was a step with a rather high energy demand. The resulting product is dried, preferably by spray drying or by another appropriate means. The dried product may then optionally be stored, or may be immediately further processed by adding a solvent, preferably water, to dissolve the soluble fraction of the dried product, which is enriched in the undesirable color and flavor fractions. The non-soluble fraction, which is enriched in isoflavones, can then be separated from the soluble fraction by any conventional means, and dried preferably by spray drying.
In keeping with a still further aspect of the invention and in order to fine tune the characteristics of the product, the product is dried to a powder. Then, a plurality of lots may be blended together to achieve a standard isoflavone level. When the product is ready for use as, for example, in a food ingredient or the like, the blended product may be rehydrated.
There are many advantages resulting from the process of drying, adding an ingredient, blending, and then rehydrating since it permits storage in a dry form, better blending, and closer control over the specifications of the final product. It is easier to control product specifications by a blending of optimally selected dry ingredients. Also, dry storage smoothes production and enables sudden large orders to be filled quickly. Thus, quality control is made easier.
In addition, there is less equipment usage since it is no longer necessary to have large batches of product sitting in expensive tanks over long periods of time (often as much as two days) during which crystals are separated from their mother liquid. Since the product may be held in storage in a dry form, there is a less likelihood that contamination might occur. There is a larger commercial market for dry powder than there is for a liquid product. The dry product better enables a final usage in many forms such as pills, liquids, health bars, ingredients for various foods, and the like.